The average American adult reads at roughly a 7th to 8th grade level. That's not an insult. It's a measurement from the National Center for Education Statistics, based on the most comprehensive literacy survey ever conducted in the United States. It means that content written at a 12th grade reading level or above is functionally inaccessible to about half the adult population. And most business websites write well above that threshold without even knowing it.
This matters for two reasons. First, if your target customer can't easily read your product page, they won't buy from it. They'll leave and find a competitor whose copy is simpler. Second, Google has been increasingly explicit that content should match the reading level of its intended audience. The helpful content system rewards pages that serve real users well, and a page that's difficult for its intended audience to read doesn't serve them well.
Why reading level creeps upward
Most business owners and marketing teams write at their own reading level, not their audience's. If you have a graduate degree and spend your days reading industry publications, your default writing voice will land at grade 12-16. That's natural. It's also a problem when your audience is homeowners looking for a plumber or small business owners trying to figure out their taxes.
Technical jargon is the obvious culprit, but sentence structure is the bigger one. Long sentences with multiple subordinate clauses are harder to parse than short declarative ones, regardless of vocabulary. A sentence like "The implementation of our proprietary methodology, which has been validated through extensive third-party audits, ensures compliance with all applicable regulatory frameworks" reads at grade 16+. "Our method has been tested by outside auditors. It meets all regulations." reads at grade 6. Same information. One version serves the audience, the other serves the writer's ego.
Passive voice compounds the problem. "The report was reviewed by the compliance team" is harder to process than "The compliance team reviewed the report." Every passive construction adds cognitive load, and the effect accumulates across a full page.
What the scores actually measure
The two most widely used readability formulas are Flesch-Kincaid Grade Level and Automated Readability Index (ARI). Both produce a U.S. grade level number. A score of 8 means an average 8th grader could understand the text. A score of 14 means you need a college sophomore's reading ability.
Flesch-Kincaid uses average sentence length and average syllable count per word. ARI uses average sentence length and average character count per word. Neither is perfect. Both can be fooled by short sentences full of jargon, or by long sentences that are actually quite clear. But as a screening tool for your own content, they're fast, free, and directionally accurate.
The Flesch Reading Ease score inverts the scale: higher is easier. A score of 60-70 is considered standard. Below 30 is very difficult. Most academic papers land around 10-20. Most successful consumer websites land around 50-70.
Matching content to audience
The right reading level depends on who you're writing for. Medical journal articles should be written at a professional level for a professional audience. But patient-facing health information should be at grade 6-8, which is why the NIH and CDC target that range for public materials.
For most business websites targeting general consumers, aim for grade 7-9. For B2B content targeting technical decision-makers, grade 10-12 is appropriate. For legal or financial disclosures, write as simply as the law allows (most don't allow as much complexity as lawyers think they do).
The goal isn't dumbing down your content. It's respecting your reader's time and cognitive budget. People browsing your site at 10 PM after a long day don't want to parse academic prose. They want to understand what you offer and whether it solves their problem.
What the audit checks
The Readability & Reading-Level Analyzer runs Flesch-Kincaid Grade Level, ARI, and passive voice detection on any page's content. It strips out navigation, headers, and boilerplate to focus on the actual body text. You get a grade level, a reading ease score, a passive voice percentage, and specific guidance on what to target for your content type.
Pair this with the Heading Gap Audit to make sure your page structure supports scanability alongside readability, and the Paragraph Semantic Density tool to check whether individual paragraphs are carrying too much information.
In The $20 Dollar Agency, I cover how clarity in client-facing materials directly affects conversion rates. Reading level isn't a vanity metric. It's a filter between your content and your revenue.
Fact-check notes and sources
- U.S. adult literacy levels: National Center for Education Statistics (NCES), PIAAC survey (Program for the International Assessment of Adult Competencies). Average U.S. adult prose literacy is at Level 2 on a 5-level scale, corresponding roughly to grades 7-8.
- NIH health literacy guidelines recommend patient-facing materials at or below a 6th-8th grade reading level. Source: NIH Clear Communication initiative.
- Flesch-Kincaid readability formula: Kincaid, J.P. et al. (1975), "Derivation of New Readability Formulas for Navy Enlisted Personnel," Naval Training Analysis Center.
- Automated Readability Index: Senter, R.J. & Smith, E.A. (1967), "Automated Readability Index," Wright-Patterson Air Force Base.
Related reading
- Heading Gap Audit — page structure that supports scanability
- Paragraph Semantic Density — information overload at the paragraph level
- Content Decay — high reading levels accelerate content abandonment
- AI Content Disclosure — AI-generated content often has unnaturally consistent reading levels
- Passage Retrievability — simpler language improves how well AI systems can extract your content
This post is informational, not educational or reading-science advice. Statistical references are to publicly available government data. No affiliation is implied.
